immunity?

• What is the immune system?

  A group of cells, tissues, and organs that detects and attacks pathogens in the body to fight disease
• How does the immune system identify foreign substances?

  It attacks anything it thinks is foreign to the body
• What can happen if the immune system malfunctions?

  It can attack the body's own cells and tissues or overreact to harmless substances
• What are the main functions of white blood cells in the immune system?

  Producing antibodies, producing antitoxins, and phagocytosis
• What is phagocytosis?

  It is the process of engulfing and digesting pathogens
• What are antigens?

  Substances that cause white blood cells to produce antibodies
• Where are antigens found?

  On the cell surfaces of pathogens
• What are antibodies?

  Proteins produced by certain white blood cells that bind to antigens
• How do antibodies function in the immune response?

  They bind to antigens found on pathogens, marking them for destruction by white blood cells
• What is the specificity of antibodies in relation to antigens?

  An antibody can only bind to a specific antigen
• What are antigen-binding sites on antibodies?

  Special areas on an antibody that allow it to bind to a specific antigen
• What are the steps of how a vaccination works?

  1. A small amount of a dead or inactive pathogen is injected into the body.
  2. White blood cells produce antibodies specific to the pathogen's antigens.
  3. If the live pathogen enters the body later, white blood cells recognize it and quickly make the correct antibodies to prevent an infection.
• What is the effect of vaccinating a large proportion of a population against a pathogen?

  It reduces the spread of the pathogen to people who can't or won't be vaccinated
• What is 'herd immunity'?

  It protects people who are too young, old, or sick to be vaccinated